Hoping someone here can help with this, since calling T-mobile is of no help...

Have an 8320 with T-Mobile specifically for the ability to make UMA calls in my apartment, where I have weak to no cell signal. It works off and on, which is frustrating when trying to resolve the problem - on perhaps half the calls, there is one way audio. Every time, the other end cannot hear me but I can hear them. The problem only has occurred on UMA on my router; I have not tried it on other wifi networks. Never has occurred on the cell network; in fact, one time I happened to switch from EDGE to UMA as I walked in to the apartment and as expected, the other party suddenly could not hear me. (As opposed to the usual situation of the call being completely dropped upon switching)

This has happened for both incoming and outgoing calls. When it's in the one-way audio mood, it seems to stay that way for some time (hanging up and calling back doesn't help). My last call to support (during a binge of one-way audio) had me do a battery pull and re-configure of the network info on the 8320 - this fixed it, but obviously this is not an acceptable solution. Since UMA does work fine some of the time, I'm leaning toward it not being a problem with my non-Tmobile Dlink router. I've started to log when it works and doesn't but no patterns are emerging. I'm pretty much at a loss - any ideas would be appreciated!

Try a VOIP test on your pc to see how the connection quality is.

MySpeed VoIP connection test, VoIP test, test VoIP performance, test VoIP quality

It might be the router. If you can get into the settings, it helps to prioritize the 8320. It could be shown as a QOS (Quality of Service) setting or just a setting to prioritize it.

VOIP quality is great - I actually have Skype on my computer. That test site reported no problems.

My router is getting old and doesn't have any QoS features or prioritization. However, I don't think it's a bandwith problem since the problem still occurs when I have virtually no other internet activity. For the record, I have AT&T DSL with about 2.5 Mbps down and 370 kbs up.

370 kbs is a little bit limited. I think 90k is the minimum for VOIP.

Check for a firmware upgrade for your router. You can also try putting dd-wrt firmware on there. Works great for lots of folks here since it has lots of customizable options:

Here's the list of supported D-Link routers.
Supported Devices - DD-WRT Wiki

Update: today I had a successful UMA call on another router in someone else's house. However, this doesn't mean much since I don't know if it would always work there.

I can't say I think my upload speed is the problem, since UMA does work perfectly fine when it does work - it either works or it doesn't with nothing in between so far. I would expect lag or distortion if the upload speed was a problem, or for it to never work at all (again, I have not been running any downloads/uploads so nearly all my bandwidth is available to the phone)

Alas, the last firmware update for my router happened in 2006 and I have it. And it is not listed as supported for the open source firmware, but thanks for letting me know about that.

I wonder if I should buy a new router... Unfortunately I don't have a spare lying around to test. Since the one I have works fine otherwise it would suck to buy one for nothing.

The Tmobile support person said that one-way audio was a common problem but I have seen very few reports of my situation on forums...?

Update: Updated firmware to 4.5.0.81 / 4.5.0.55 and haven't experienced one-way audio yet... The phone does often try to switch to the cell network upon attempting a call over UMA, which causes the call to fail, but this isn't nearly as annoying a problem and I can live with it.

Keeping fingers crossed.

Reviving my old thread here... Still getting one-way audio (I hear them, they don't hear me) on most UMA calls. Dlink router w/ newest firmware - not Tmobile "certified" or whatever. Since some UMA calls are fine, I'm pretty sure it is not blackberry settings, router settings, or bandwidth (none of these are correlated with when it works or doesn't).

Resetting the 8320 does fix it, but this is clearly not a solution.

Anyone out there have experience with this same problem (one-way audio on UMA)? Using the newest .108/.81 firmware to no avail. Seems to actually happen more often with this new firmware.

Since you said you were "reviving your old thread" I moved your post into your original thread.